Medieval lawsuits from the highest courts of England and France show the concern of authorities for even minor issues involving ordinary people – a democratic and modern trait. In comparing the English Court of Common Pleas to the Parlement of Paris, it can be seen that classical Roman law made a great impact on France, while the English Court ignored Roman law and applied English customary law and acts of Parliament. The Parlement of Paris also had to apply local customs, but its judges had all studied Roman and no customary law at the university; however, for political reasons they were not allowed to refer openly to the Roman law in which they had been educated. The jury was a major medieval contribution to modern democratic thinking, as was the political idea that matters concerning the whole community ought to be decided by all its members. The American power-sharing system, between President and Congress, continues the late medieval balance between King and Parliament. English common law was one of the great creations of the Middle Ages and the only system of comparable importance is continental civil law (with Germanic and Roman roots). This paper considers the chances of the elaboration in the 21st century of a common European law combining elements from both traditions.